TWI778715B - Backlight module and display device - Google Patents

Abstract

A backlight module includes at least one optical film and a backlight unit. The optical film has a light entrance side and a light exit side opposite to the light entrance side. A plurality of light entrance microstructures are formed on the light entrance side, and the light entrance microstructures are cone-shaped structures. The backlight unit is arranged on the light incident side of the optical film and includes a light source. The structural design of the light incident microstructure of the optical film can expand the light field of the light source to achieve the purpose of emitting light at a specific angle. The invention also provides a display device containing the backlight module.

Description

Backlight module and display device

The present invention relates to an optical element, in particular to a backlight module and a display device with a special light angle.

With the expansion of liquid crystal displays (LCDs) in applications such as mobile phones, on-board displays, personal digital assistants (PDAs), and televisions, a higher level of backlight technology based on light guide plates has been proposed. Requirements, such as: high brightness, low cost, low energy consumption, thin and light, etc.

Taking a vehicle-mounted display as an example, its viewing angle needs to be extremely wide in the horizontal direction, but the existing backlight module architecture cannot meet the special viewing angle requirements of the vehicle-mounted display.

Therefore, the purpose of the present invention is to provide a backlight module that can expand the light field and generate a specific light angle.

The backlight module includes at least one optical film and a backlight unit. The optical film has a light incident side and a light exit side opposite to the light incident side. A plurality of light incident microstructures are formed on the light incident side, and the light incident microstructures are tapered structures. The backlight unit is disposed on the light incident side of the optical film, and includes a light source.

Another technical means of the present invention is that each of the light incident microstructures has a plurality of sides, a vertex and a central line, the central line is perpendicular to the light incident side of the optical film, and the vertex is located at the On the central line, the side surfaces take the vertex as a joint point and the adjacent edges are jointed with each other to form a composite surface.

Another technical means of the present invention is to define the extending direction of the optical film to have an X-axis and a Y-axis perpendicular to the X-axis, and the light incident microstructures have the same slope in the X-axis direction and are A first optical surface and a second optical surface that are symmetrically arranged have a third optical surface and a fourth optical surface that have the same slope in the direction of the Y-axis and are symmetrically arranged, and the light incident microstructure is a symmetrical pyramid shape.

Another technical means of the present invention is that a plurality of light-emitting microstructures are formed on the light-emitting side of the optical film, and the light-emitting microstructures are convex.

Another technical means of the present invention is that the backlight unit further includes a diffuser plate for receiving light from the light source, the light source has a circuit board, and a plurality of light emitting diodes disposed on the circuit board, and the light source has a circuit board. The diffuser plate has a bottom surface and a light emitting surface opposite to the bottom surface, the bottom surface faces the circuit board, and the light emitting surface faces the optical film.

Another technical means of the present invention is that the backlight unit further includes a light guide plate for receiving light from the light source, the light source has a circuit board, and a plurality of light emitting diodes disposed on the circuit board, and the light source has a circuit board. The light guide plate has a side surface and a light emitting surface connected to the side surface, the side surface faces the circuit board, and the light emitting surface faces the optical film.

Another technical means of the present invention is that the optical film includes a base material layer, a structural layer disposed on one side of the base material layer, and a diffusion particle layer disposed on the other side of the base material layer , the light incident microstructure is formed on the structure layer.

Another technical means of the present invention is to define the extending direction of the optical film to have an X-axis and a Y-axis perpendicular to the X-axis, and the light incident microstructures have different slopes in the direction of the X-axis and are A first optical surface and a second optical surface that are asymmetrically arranged have a third optical surface and a fourth optical surface that are symmetrically arranged with the same slope in the direction of the Y-axis, and the light incident microstructure is asymmetrical Pyramid shape.

Another technical means of the present invention is that the backlight module further includes a grating layer located on the light-emitting side of the optical film, the grating layer has a plurality of baffles, and a plurality of light-transmitting portions located between adjacent baffles , the baffles are spaced and inclined along the direction of the X-axis, and extend along the direction of the Y-axis.

Another technical means of the present invention is that the light source has a circuit board, a plurality of light-emitting diodes disposed on the circuit board, and a light-transmitting glue layer covering the light-emitting diodes, the light-emitting diodes The body is a blue light source, and the backlight module further includes a fluorescent film, which is used for matching with the light-emitting diodes to convert the blue light source into a white light source, wherein the backlight unit further includes a light source for receiving the light source. light diffuser or diffuser.

Another object of the present invention is to provide a display device comprising a backlight module as described above, and a display panel disposed on the backlight module.

The effect of the present invention is that, through the structural design of the light incident microstructure of the optical film, the light field of the light source can be further expanded, so as to achieve the purpose of emitting light at a specific angle.

The features and technical contents of the relevant patent applications of the present invention will be clearly presented in the following detailed description of the preferred embodiments with reference to the drawings. Before the detailed description, it should be noted that similar elements are designated by the same reference numerals.

Referring to FIG. 1 , it is a first preferred embodiment of the backlight module of the present invention, which includes an optical film 2 and a backlight unit 3 . In some embodiments, the backlight unit 3 includes a direct-type light source 31 , a diffuser plate 32 for receiving light from the light source 31 , a diffuser sheet 33 stacked on the diffuser plate 32 , and a diffuser plate 33 . The brightness enhancement film 34 on the light-emitting side of the diffuser 33 . The light source 31 has a circuit board 311 and a plurality of light emitting diodes 312 disposed on the circuit board 311 , and the diffuser plate 32 has a bottom surface 321 and a light emitting surface 322 opposite to the bottom surface 321 . 321 faces the circuit board 311 , and the light emitting surface 322 faces the diffuser 32 . Referring to FIG. 2 , in another embodiment, the backlight unit 3 includes a side-illuminated light source 31 , a light guide plate 35 for receiving light from the light source, and a diffusion sheet stacked on the light guide plate 35 33 , and a brightness enhancement film 34 located on the light-emitting side of the diffusing sheet 33 . The light guide plate 35 has a light incident surface 351 facing the circuit board 311 and a light exit surface 352 connected to the light incident surface 351 . The light exit surface 352 faces the diffuser 33 . As shown in FIG. 3 , a display panel 36 is disposed on the light-emitting side of the brightness enhancement film 34 to form a display device. It should be noted that, in order to clearly show the structure of each element, each element is separated from each other. In actual use, each element is in a state of being closely stacked, and the same is true for the following embodiments.

Referring to FIG. 1 and FIG. 2 , in this embodiment, the optical film 2 is disposed between the diffuser 33 and the brightness enhancement film 34 , and is a high-density film with microstructures formed on both sides. More specifically, the optical film 2 has a light incident side 21 and a light exit side 22 opposite to the light incident side 21 . The light incident side 21 faces the diffuser 33 and the light exit side 22 faces the light exit side 22 . Brightness Enhancement Film 34 . The light emitting side 22 is formed with a plurality of light emitting microstructures 23, and the light emitting microstructures 23 are convex. A plurality of light incident microstructures 24 are formed on the light incident side 21 , wherein the light incident microstructures 24 are tapered structures. When the light from the light emitting diode 312 enters the light incident microstructure 24 of the optical film 2 , since the light incident microstructure 24 is a conical structure with multiple sides, no matter whether it is in the X-axis Or in the direction of the Y-axis, the light can be refracted outward through the multiple side surfaces of the light incident microstructure 24 to produce a light splitting effect, and the directional light source of the light emitting diode 312 can be homogenized. In addition, it should be noted that the conical structure of the light incident microstructures 24 is not limited to concave or convex, and can also make the light field of the light source 31 more spread. The concave design adopted by the structure can avoid scratching the diffusion sheet 33 stacked below it.

As shown in FIG. 4 , each of the light incident microstructures 24 is a quadrangular pyramid-shaped structure, having four sides 241 , a vertex P and a center line C, the center line C being perpendicular to the entrance of the optical film 2 . The light side 21, and the vertex P is located on the center line C, wherein the side surface 241 uses the vertex P as a joint point and adjacent edges are joined to each other to form a composite surface. In more detail, it is defined that the extending direction of the optical film 2 has an X axis and a Y axis perpendicular to the X axis. The light incident microstructures 24 have the same slope and are symmetrically arranged in the X axis direction. A first optical surface 241a and a second optical surface 241b have a third optical surface 241c and a fourth optical surface 241d with the same slope in the direction of the Y-axis and are symmetrically arranged, so the light incident microstructure 24 is Symmetrical pyramid shape.

Since each of the light incident microstructures 24 has the first to fourth optical surfaces 241a˜241d, when the light of the light emitting diode 312 enters the light incident microstructure 24 of the optical film 2, no matter In the X-axis or the Y-axis direction, the light can be refracted outward through the side surface 241 to produce a light splitting effect, and the directional light source of the light emitting diode 312 can be uniformized. As shown in FIG. 5 , compared with the general backlight module (shown by the dotted line), the use of the optical film 2 in the preferred embodiment (shown by the solid line) can slightly reduce the brightness at the middle viewing angle (also shown by the solid line). That is, the area between the solid line and the dotted line between -40 degrees and +40 degrees is small), but at the same time, it can greatly improve the brightness of the large viewing angles on both sides (that is, outside the -40 degrees to +40 degrees. The area between the solid line and the dashed line is larger), which makes the distribution of the light field wider, and is also suitable for vehicle-mounted equipment. The need for a wide viewing angle.

Referring to FIG. 6 , it is a second preferred embodiment of the backlight module of the present invention, comprising at least one optical film 4 and a backlight unit 5 . The backlight unit 5 includes a light source 51 , a diffuser plate 52 for receiving light from the light source 51 , a fluorescent film 53 located on the light-emitting side of the diffuser plate 52 , and a plurality of Brightness Enhancement Film 54 . In this embodiment, two optical films 4 are stacked between the diffusion plate 52 and the fluorescent film 53 . The light source 51 is a direct light source and has a circuit board 511 , a plurality of light-emitting diodes 512 disposed on the circuit board 511 , and a light-transmitting glue layer 513 covering the light-emitting diodes. The light emitting diode 512 is a blue light source, and the fluorescent film 53 is used to cooperate with the light emitting diode 512 to convert the blue light source into a white light source.

Referring to FIG. 7 , each optical film 4 includes a base material layer 41 , a structure layer 42 disposed on one side of the base material layer 41 , and a diffusion particle disposed on the other side of the base material layer 41 . layer 43 , a plurality of light incident microstructures 44 are formed on the side of the structure layer 42 facing the diffuser plate 52 . The light incident microstructure 44 is a cone-shaped structure. In this embodiment, the cone-shaped structure adopts a convex design, and is the same symmetrical pyramid shape as the first preferred embodiment. The light field of the light source 31 is further expanded.

Referring to FIGS. 6 and 7 , in this embodiment, the optical film 4 can achieve the effect of spreading the light of the light source 51 more through the design of the light incident microstructure 44 , in order to meet the requirements of vehicle models to simultaneously A special wide viewing angle is often required for the purpose of viewing the driver's seat and the passenger seat at the same time. The optical film 4 can also pass through the diffusion particle layer 43 to make the light passing through the structural layer 42 and the base material layer 41 have a better uniform light effect, which can further homogenize the light directly above the light emitting diodes 512 The bright spot area and the dark shadow area between the light emitting diodes 512 are reduced to reduce the phenomenon of hot spots. In this embodiment, two layers of the optical film 4 are stacked, which has a multiplication effect. Since the optical film 4 can greatly improve the uniformity of light, the required light mixing distance between the light source 51 and the diffusion plate 52 can be shortened, which is beneficial to the thinning of the overall structure. At the same time, the filling material (such as Polycarbonate, PC) used to support the diffuser plate 52 and other optical films on the light-transmitting adhesive layer 513 in the prior art is eliminated, thereby reducing material costs and reducing The stacking thickness of the filling material can also facilitate further thinning of the overall structure.

Referring to FIG. 8 , it is a third preferred embodiment of the backlight module of the present invention, comprising an optical film 6 , a backlight unit 7 , and a grating layer 8 . The backlight unit 7 includes a light source 71 , a diffusion sheet 72 for receiving light from the light source 71 , and a fluorescent film 73 on the light-emitting side of the diffusion sheet 72 . The optical film 6 is disposed between the fluorescent film 73 and the grating layer 8 . The fluorescent film 73 is also used to convert the blue light source into a white light source.

The optical film 6 has a light incident side 61 and a light exit side 62 opposite to the light incident side 61 . The light incident side 61 faces the fluorescent film 73 , and the light exit side 62 faces the grating layer 8 . A plurality of light incident microstructures 63 are formed on the light incident side 61 , and the light incident microstructures 63 are tapered structures. In this embodiment, a concave design is further adopted for the conical structure, so as to avoid scratching the fluorescent film 73 stacked under it. In more detail, as shown in FIG. 9 , the extending direction of the optical film 6 is defined to have an X-axis and a Y-axis perpendicular to the X-axis, and the light incident microstructures 63 have a slope in the direction of the X-axis A first optical surface 631a and a second optical surface 631b which are different and are arranged asymmetrically have a third optical surface 631c and a fourth optical surface 631d which are symmetrically arranged with the same slope in the direction of the Y-axis. The light incident microstructures 63 are asymmetrical pyramids. In FIG. 9 , the light incident microstructures 63 are arranged in a continuous arrangement, and in some embodiments, they may also be discontinuous arrangement, and adjacent light incident microstructures 63 are connected by planes to avoid scratches and overlaps. The fluorescent film 73 below it.

As shown in FIG. 8 , the grating layer 8 has a plurality of baffles 81 and a plurality of light-transmitting parts 82 located between adjacent baffles 81 , and the baffles 81 are spaced and inclined along the direction of the X-axis, and extends along the Y-axis.

When the light passes through the optical film 6, in addition to the light-incident microstructure 63, the light-splitting effect can be produced, and the asymmetric pyramid-shaped design can also deflect the light-splitting to a specific direction, and cooperate with the grating layer. 8, the light will be emitted from the light-transmitting portion 82 of the grating layer 8. Therefore, as long as the inclination angle of the baffle plate 81 is adjusted, the light exit direction after passing through the grating layer 8 can be changed, thereby adjusting the distribution of the light field. As shown in FIG. 10 , using the design of the preferred embodiment, the light exit direction can be deviated to one side.

Taking the application to the vehicle dashboard as an example, due to the large amount of information that needs to be displayed on the dashboard, the display area is usually a rectangle that extends laterally instead of a square. Therefore, in this embodiment, the design of the optical film 6 and the grating layer 8 are used. , to deflect the light in a specific direction, such as providing driving information toward the driver's seat, so as to meet the asymmetric viewing angle requirements of vehicle display devices. At the same time, the slopes of the optical surfaces 631a-631d and the inclination direction and angle of the baffle plate 81 of the grating layer 8 can be adjusted to meet the requirements of various special viewing angles, depending on the use environment.

To sum up, the light incident microstructure of the present invention through the optical film is a symmetrical or asymmetrical pyramid-shaped structure design, so when the light passes through the light incident microstructure, both the X-axis and the Y-axis direction are It can refract the light outward to produce a spectroscopic effect, and homogenize the directional light source to meet the special wide viewing angle that is often required by vehicle models for the purpose of allowing the driver's seat and the auxiliary seat to watch at the same time. The asymmetrical pyramid shape can further offset the light in a specific direction, such as providing driving information in the direction of the driver's seat, so as to meet the requirements of a special viewing angle, which can indeed achieve the purpose of the present invention.

However, the above are only preferred embodiments of the present invention, and should not limit the scope of the present invention, that is, any simple equivalent changes and modifications made according to the scope of the patent application of the present invention and the contents of the description of the invention, All still fall within the scope of the patent of the present invention.

2: Optical film 21: light-incident side 22: light-emitting side 23: Light-emitting microstructure 24: Incoming light microstructure 241: Side 241a: First Optical Surface 241b: Second Optical Surface 241c: Third Optical Surface 241d: Fourth Optical Surface 3: Backlight unit 31: Light source 311: circuit board 312: Light Emitting Diode 32: Diffuser plate 321: Underside 322: light-emitting surface 33: Diffuser 34: Brightening film 35: light guide plate 351: light incident surface 352: light-emitting surface 36: Display panel 4: Optical film 41: substrate layer 42: Structural Layer 43: Diffusion particle layer 44: Incoming light microstructure 5: Backlight unit 51: Light source 511: circuit board 512: Light Emitting Diode 513: Translucent glue layer 52: Diffuser plate 53: Fluorescent film 54: Brightness Enhancement Film 6: Optical film 61: light incident side 62: light-emitting side 63: Incoming light microstructure 631a: First Optical Surface 631b: Second Optical Surface 631c: Third Optical Surface 631d: Fourth Optical Surface 7: Backlight unit 71: Light source 72: Diffuser 73: Fluorescent film 8: Grating layer 81: Baffle 82: Translucent part P: vertex C: Central line X, Y: Axial

FIG. 1 is a schematic diagram, which is a first preferred embodiment of the backlight module of the present invention, wherein a light source is a direct light source; FIG. 2 is a schematic diagram, which is another form of the first preferred embodiment, wherein the light source is an edge-type light source; FIG. 3 is a schematic diagram of a preferred embodiment of the display device of the present invention; Fig. 4 is a schematic diagram illustrating that a light incident microstructure is a symmetrical pyramid shape; FIG. 5 is a graph illustrating that the optical film of the present invention can reduce the brightness of the middle viewing angle and simultaneously improve the brightness of the large viewing angles on both sides; FIG. 6 is a schematic diagram of a second preferred embodiment of the backlight module of the present invention; 7 is a schematic diagram illustrating the structure of the optical film of the second preferred embodiment; FIG. 8 is a schematic diagram of a third preferred embodiment of the backlight module of the present invention; 9 is a schematic diagram illustrating the structure of the optical film of the third preferred embodiment; and FIG. 10 is a schematic diagram illustrating the simulation of the light exit angle of the third preferred embodiment.

2: Optical film

21: light-incident side

22: light-emitting side

23: Light-emitting microstructure

24: Incoming light microstructure

3: Backlight unit

31: Light source

311: circuit board

312: Light Emitting Diode

32: Diffuser plate

321: Underside

322: light-emitting surface

33: Diffuser

34: Brightening film

Claims (8)

A backlight module, comprising: at least one optical film with a light incident side and a light exit side opposite to the light incident side, a plurality of light incident microstructures are formed on the light incident side, the light incident microstructures It is a cone-shaped structure; and a backlight unit is arranged on the light incident side of the optical film, and includes a light source; wherein, the extension direction of the optical film is defined to have an X axis, and a Y perpendicular to the X axis The light incident microstructure has a first optical surface and a second optical surface with different slopes in the direction of the X axis and are asymmetrically arranged, and has a third optical surface with the same slope and a symmetrical arrangement in the direction of the Y axis The optical surface and a fourth optical surface, the light incident microstructure is an asymmetric pyramid shape. The backlight module of claim 1, wherein a plurality of light-emitting microstructures are formed on the light-emitting side of the optical film, and the light-emitting microstructures are convex. The backlight module of claim 2, wherein the backlight unit further comprises a diffuser plate for receiving light from the light source, the light source has a circuit board, and a plurality of light emitting diodes disposed on the circuit board , and the diffuser plate has a bottom surface and a light-emitting surface opposite to the bottom surface, the bottom surface is facing the circuit board, and the light-emitting surface is facing the optical film. The backlight module of claim 2, wherein the backlight unit further comprises a light guide plate for receiving light from the light source, the light source has a circuit board, and a plurality of light emitting diodes disposed on the circuit board , and the light guide plate has a side with A light emitting surface is connected to the side surface, the side surface faces the circuit board, and the light emitting surface faces the optical film. The backlight module of claim 1, wherein the optical film comprises a base material layer, a structural layer disposed on one side of the base material layer, and a structure layer disposed on the other side of the base material layer A diffusion particle layer, on which the light incident microstructure is formed. The backlight module of claim 1, wherein the backlight module further comprises a grating layer on the light-emitting side of the optical film, the grating layer has a plurality of baffles, and a plurality of baffles located between adjacent baffles In the light-transmitting part, the baffles are spaced and inclined along the X-axis direction, and extend along the Y-axis direction. The backlight module according to any one of claims 5 to 6, wherein the light source has a circuit board, a plurality of light-emitting diodes disposed on the circuit board, and a transparent cover covering the light-emitting diodes. The light emitting diode is a blue light source, the backlight unit also includes a fluorescent film, and a diffusion plate or a diffusion sheet for receiving the light of the light source, the fluorescent film is used for interacting with all the light sources. The light-emitting diodes are matched to convert the blue light source into a white light source. A display device, comprising the backlight module according to any one of claim 1 to claim 7, and a display panel disposed on the backlight module.

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